It's not often someone can say, "This is the culmination of my life's work," and mean it. Rarer still is someone whose "life's work" encompasses not just a distinguished academic and professional career, but 30-plus years of personal experience too.

But for Rupert Whitaker it is not merely doctoral qualifications (in psychiatry, neurology and immunology), post-doctoral fellowships (in HIV immunology and psychiatry), or even 15 or so years as a highly regarded specialist in behavioural medicine and chronic illness, that allows him to speak with authority on the way we define and practise medicine.

It's also the fact that his partner, Terry Higgins, was, in July 1982, one of the first people in Britain to die from Aids, leading to Whitaker – then still in his teens – co-founding the Terrence Higgins Trust, now Europe's largest HIV/Aids charity. And that for three decades now he has himself been living with HIV (and a few other illnesses too).

It is, by any standards, a fairly remarkable accumulation of knowledge and experience. "I've worn a number of hats in my life – academic, practitioner," admits Whitaker. "But it's bringing that together with my experience as a patient that's convinced me things have to change. We have to start seeing medicine in terms of what ill people need. We have to get away from the provider-centred approach that 'Doctor knows best.'"

With this objective in mind, in 2007 Whitaker founded the Tuke Institute - an independent thinktank of scientists, clinicians and professionals from around the world. Tuke aims to promote standards and methods in patient- centred, health-driven medicine, preventing malpractice, measuring outcomes from the patient's perspective, assessing clinicians' performance and encouraging public participation in running – and auditing – health services.

It was born of a traumatic experience. "For some reason I handled my first HIV infection, in 1981, very well," says Whitaker. "I didn't expect to live a year, but I did. But in 1990 I was reinfected, with a particularly virulent strain. Then shortly afterwards, I had a stroke. It was nothing to do with the HIV, but it caused various problems that required brain surgery and left me with epilepsy. What happened after that was key."

Whitaker developed a further illness, a chronic neurological disorder that meant "I was walking by hanging on to the wall, dragging my legs. It was quite dramatic. It wasn't diagnosed after two years of NHS care, and the Institute of Neurology in London accused me of making it up. Eventually I went to the States, and the illness was diagnosed in 10 days."

The particular class of HIV medication Whitaker was taking had been interacting with the brain damage caused by his stroke. "I just couldn't handle any of that class of medication," he says. "It made me extremely sick." But his treatment, he says, had been "symptomatic of the problems we have with how medicine is delivered as a service to the public. We have to see patients as people, not collections of diseases."

After many years working in the US, Whitaker still believes in the principles of the NHS. "Medical services," he says, "can never really be health-effective unless you have socialised medicine. But the system has to be a real participative democracy, so it's about the services patients actually need, not those that doctors think they do. The focus has to be: what does this person need to get well, and to stay well."

This is all the more important, he says, because of the growing numbers of people living with chronic illnesses: HIV, heart disease, lung disease, diabetes. "The government wants these people to lead normal lives back at work," he says, "but the NHS can't help them do that. It's not set up for it. It's a disease service rather than a health service. It's trying to offer a pill-based solution rather than adapting its services to a new reality."

There has been some change, Whitaker accepts. "Thirty years ago, it was totally physician-centred," he says, but it is still "far from what patients really need". He is well aware that trying to reverse "centuries of medical culture and vested interests" will be "a long haul". It's no accident, he says, if many of the medical professionals and clinicians who have welcomed the Tuke Institute have chronic diseases themselves: "You can't really understand, until you've been through it, what a person needs to get well."

Whitaker does not see himself as in any way exceptional. "Everyone's exceptional in their own way. Some of my patients, I see them struggling . . . I feel grateful actually, for me: it could have been worse. But I've always been a pragmatic pessimist: I've seen what could go wrong, and I've fought as hard as I can to make sure that it doesn't. And I'm a real fighter."

But a lifetime's work on HIV and Aids (still, despite the success of combination therapies, "a very dangerous infectious disease, the more so because of the degree of complacency that has now crept in around it – people just think, I'll be fine"), a struggle without which "frankly, I'd probably be dead", has, he says, led him to this: the larger issue that HIV represents, "the burden of chronic illness, and how we address it. It's a complex area, how we get and stay well: it's biological, psychological, social, behavioural. But I'm a fighter. The penny will drop eventually."